The father of a 38-year-old Lathrop man accused of allegedly killing his wife with a screwdriver says his son is mentally disabled.

The San Joaquin County Sheriff's Office says Charlie Dumlao called 911 just after midnight Sunday and said he had killed his wife, 43-year-old Evangeline Guillermo Dumlao. The couple's two children, ages 7 and 10 months, were injured.

The Stockton Record reports that Dumlao is expected to be formally charged Wednesday with one count of premeditated murder and two counts of attempted murder.

His father, Leonard Dumlao, says he's been his son's legal guardian since he fractured his skull in 2005.

Charlie Dumlao was charged with battery on a peace officer in 2008, but was found not competent to stand trial and placed in a mental health facility.